Tetra controls manufactures digitally controlled on-line digital ups systems. These ups systems are available with salient features like digital sine wave generation, on-line diagnostics, synchronised static by-pass switch, digitally controlled business logic, active emi cancellation technique, alpha numeric back light lcd, rs 232 to connect with host computer, igbt short circuit protection by software and over temperature shut down. The on-line digital ups systems have a reliable operation in normal mode with 165 v to 260 v input voltage supply and 230v ± 1% steady output voltage. The digital ups systems are available with technical specifications like more than 87% efficiency; saves running cost; high sinusoidal voltage; 230 v ac single-phase low harmonic distortion; modular design; igbt based double conversion and emi line filters.